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ATLAS : status, limitations and upgrade plans

ATLAS : status, limitations and upgrade plans. TIPP 2011 09.06.2011 T. Kawamoto on behalf of ATLAS collaboration. ATLAS detector. Central trackers in a solenoidal magnet EM + hadronic calorimeters Muon spectrometer in toroidal magnets

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ATLAS : status, limitations and upgrade plans

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  1. ATLAS : status, limitations and upgrade plans TIPP 2011 09.06.2011 T. Kawamoto on behalf of ATLAS collaboration T. Kawamoto

  2. ATLAS detector • Central trackers in a solenoidal magnet • EM + hadronic calorimeters • Muon spectrometer in toroidal magnets • Forward detectors |h | < 2.5 |h | < 5 |h | < 2.7 T. Kawamoto

  3. ATLAS detector Inner tracking Straw tubes Silicon strip Silicon pixel T. Kawamoto

  4. ATLAS detector Calorimeters T. Kawamoto

  5. ATLAS detector Drift tubes (3cm Φ) Muon spectrometer RPC CSC Thin gap chambers T. Kawamoto

  6. ATLAS status LHC peak luminosity exceeded 1x1033 ATLAS has collected over 0.7 fb-1 Data taking efficiency ~ 95% T. Kawamoto

  7. ATLAS status Approximate operational fractions Number of channels (103) T. Kawamoto

  8. ATLAS status • 2011 LHC strategy of • luminosity increase is based on • large bunch current • small b* • small emittance • Average number of • pp collisions / crossing ~ 10 Pile up T. Kawamoto

  9. ATLAS status Experienced even harder conditions in the Pb – Pb collisions Possible to reconstruct Z’s, J/y’s, and others T. Kawamoto

  10. ATLAS status ATLAS had a good start, and collecting high quality data. Further details of these results and other nice results are presented in many ATLAS talks in this conference T. Kawamoto

  11. LHC and ATLAS upgrade • LHC physics goals • Improve standard model measurements (W, Z, top, …) • Higgs : understanding the electroweak symmetry breaking • Beyond the SM : SUSY, extra dimensions, • Even something totally new … • Whatever will be discovered in next years at LHC, need much data to understand • what has been discovered. • Higher luminosity allows extending discovery/studies to • higher masses • processes of lower cross-section • LHC has plans of upgrade by increasing luminosity to collect ultimately ~ 3000 fb-1 . • This will open new physics possibilities. T. Kawamoto

  12. LHC and ATLAS upgrade Possible upgrade timeline 7 TeV →14 TeV → 5x1034cm-2s-1 luminosity leveling ∫ L dt 1x1034 → ~2x1034cm-2s-1 3000 fb-1 phase-2 → 1x1034cm-2s-1 ~300 fb-1 1027→ 2x1033cm-2s-1 phase-1 ~50 fb-1 phase-0 ~10 fb-1 2013/14 2018 ~2022 Year Now T. Kawamoto

  13. ATLAS upgrade • LHC improves, bulk of luminosity with instantaneous luminosity beyond the • nominal luminosity for which the ATLAS detector was designed and built. • Technology improves, can build better performing detector now. • Detectors age, after the nominal integrated luminosity has been collected, • leading to deterioration of performance during the runs at higher luminosity. • It will take long time to study and build new detector • Installation has to be done during the limited number of long shut downs • Installation has to be planned to be prepared to the new running condition T. Kawamoto

  14. ATLAS upgrade : phase - 0 2013/14 : to prepare for the following period of a few years of √s =14 TeV, Lumi ramping up to the nominal lumi, collecting 50-100 fb-1 Very important period. Discovery and initial studies of Higgs, SUSY in the scope. Many consolidations, de-staging, new cooling system, new beam pipe (steel → Al : reducing background in the muon detector), repairs, improving reliability, … Installation of new pixel layer : IBL – a major project of phase-0 The innermost layer of Pixel detector has an important role for reconstructing secondary vertices away from the IP, vital for b-tagging, therefore referred to as the B-layer. Pixel detector and beam pipe → T. Kawamoto

  15. ATLAS upgrade : phase - 0 The current B-layer will become inefficient after phase-1 (beyond nominal luminosity): data bandwidth, radiation damages, … The idea is, instead of replacing the B-layer, which is very difficult and dangerous, add a new B-layer inside the present one. 3 pixel layers → 4 pixel layers Insert the new layer inside the current beam pipe (Insertable B-Layer → IBL) using a smaller beam pipe. Phase-1 was initially in 2016, now it is postponed to 2017 or 2018, → Advance the project schedule and install in 2013/2014. it helps anyway, improves performance less activation in earlier time (ease of installation) T. Kawamoto

  16. ATLAS upgrade : phase - 0 IBL technology • Planner silicon sensor • 3d silicon sensor • Diamond sensor → postponed for future upgrade New readout chip of higher performance Double side 3D sensor Planner sensor prototype T. Kawamoto

  17. ATLAS upgrade : phase - 1 2017 or 18 : to prepare for the following period of a few years of √s =14 TeV, Lumi beyond the nominal → 2x1034, collecting ~100 fb-1/year • Increase of cavern background : concern with muon spectrometer performance • LAr calorimeter in the forward region (FCAL) needs help (high particle rate) • Trigger upgrade needed to maintain low threshold at Level-1 • to keep the physics acceptance • Fast tracking processor (FTK) to enhance the performance of Level-2 trigger T. Kawamoto

  18. ATLAS upgrade : phase - 1 Muon small wheel : the innermost station in the endcap Preliminary Designed for MC simulation of background with safety factor x5. Measurements with collision data are confirming that the small wheel will be in critical situation at luminosity beyond the nominal → new tracker needed Max rate (data extrapolated) 150kHz/tube at 7 TeV  200 kHz/tube at 14 TeV and 1x1034 T. Kawamoto 18

  19. ATLAS upgrade : phase - 1 • Improve L1 muon trigger by integrating • small wheel in the trigger • removing background • improving pT resolution • Plan to build new small wheels for phase-1, • which comprises • precision tracker with high rate capability • fast segment reconstruction for L1 upgrade T. Kawamoto

  20. ATLAS upgrade : phase - 1 New small wheel : candidate technologies small tube fine strip TGC Large Micromegas fine strip analog readout. position resolution 60 mm used for precision tracking and L1 trigger. Success of resistive anode ensuring stability at high rate. Used for precision tracking and L1 trigger. 15 mm tube : much shorter drift time. works at x7 rate RPC is also considered for the L1 component T. Kawamoto

  21. ATLAS upgrade : phase - 1 Warm forward calorimeter Idea of placing a small warm calorimeter in front of the LAr FCAL in order to protect it from heating, ion build-up Cupper absorbers + 1 cm2 diamond sensors on ceramic highly segmented readout T. Kawamoto

  22. ATLAS upgrade : phase - 1 3-level trigger : 40 MHz → 200~300 Hz L=7x1032cm-2s-1 Level-1 : Hardware ( m, cal ) Level-2 : On a computer farm, by software, based on limited information Event filter: On a computer farm, Full reconstruction • Data recording rate (event filter output) needs to be maintained at the same level. • Need more restrictive trigger at all levels. • Need to maintain lepton and calorimeter thresholds low in order • not to lose physics acceptance T. Kawamoto

  23. ATLAS upgrade : phase - 1 L1 Trigger upgrade • Topological processor : use of topological information, e.g. lepton isolation • Improved trigger input from the muon small wheel (upgrade in the endcap) • Goal is go gain more control of L1 rate without losing physics acceptance. • Allowing L2 and Event filter to do their job to control the data recording rate. T. Kawamoto

  24. ATLAS upgrade : phase - 1 FTK for Level-2 • In the Level-2 trigger, performed by a computer farm, • Track finding • Track fitting • are time consuming processes. • Idea of performing these tasks by a dedicated hardware, gaining substantial speed. T. Kawamoto

  25. ATLAS upgrade : phase - 2 ~2022: to prepare for the following period of ~ 10 years, after having collected some 100 fb-1 at √s =14 TeV, to run at 5x nominal luminosity : 5x1034 with luminosity leveling, collecting a total of 3000 fb-1 100 or 200 interactions/crossing to disentangle, • Most of ATLAS can remain • Magnets, most of muons and calorimeters • Changes are needed in • Trigger (muon, calo) and DAQ • Possibly some of the muon chambers for high background rate • Possibly endcap and forward calorimeter • New calorimeter readout for trigger upgrade • New inner detector T. Kawamoto

  26. ATLAS upgrade : phase - 2 Trigger for phase-2 L1 Calorimeters Full readout of digitized energy from all cells over high speed optical link. bringing full granularity for L1 calorimeter trigger. Maybe already introduced in earlier phase in small scale (a slice), operated in parallel to the existing system, for evaluation. T. Kawamoto

  27. ATLAS upgrade : phase - 2 Trigger for phase-2 L1 Muons in barrel MDT pT resolution 20% → 5% at 20 GeV Sagitta measurement using 3 stations Possible use of barrel MDTs for L1 trigger to improve pTresolution at L1. (bringing a part of L2 function to L1) Overlap region This region is improved by the new small wheel : Phase - 1 T. Kawamoto

  28. ATLAS upgrade : phase - 2 Trigger for phase-2 L1 Track Ideas of implementing ID track information in L1 trigger. improving pT resolution for high pT leptons Prepare a dedicated double layer in the outer radii of ID. Find straight track segment pointing to IP as an indication of high pT track Fast readout of a part of ID modules, seeded by high pT candidates (RoI) by muon or calorimeter L1 (→ L0). High speed hardware confirm the presence of high pT leptons. Need additional data stream from front end chip. Many studies needed to know how to realize, and how to implement in ATLAS ensuring compatibility (latency, etc) with the whole system. T. Kawamoto

  29. ATLAS upgrade : phase - 2 New ID tracker • Rate : • Pixel B-layers will become inefficient at 2x1034 and significantly so at 3x1034 • SCT (strip), a part of it cannot be readout due to bandwidth limitation • TRT occupancy will become very high • Radiation damage: • SCT designed for 700 fb-1 • Much shorter life for B-layer • New technology: • New electronics for lower power consumption • New cooling and support structure for reducing materials • All new inner tracker for phase-2 • higher granularity to keep occupancy low • Improved material budget • Baseline : all silicon strip + pixel T. Kawamoto

  30. ATLAS upgrade : phase - 2 New ID tracker Lessons from the present detector Substantial material for services Layout issues T. Kawamoto

  31. ATLAS upgrade : phase - 2 New ID tracker • Studies are on going in all areas • Sensors • Readout chips • Module integration • Cooling • Powering • Layout and physics performance T. Kawamoto

  32. ATLAS upgrade : phase - 2 New ID tracker • Evaporative CO2 cooling • large latent heat • good heat transfer • allowing smaller cooling pipes • (material budget) Rad-hard strip sensors Baseline n-on-p sensors • New powering schemes • DC-DC convertors • Serial powering • being successfully tested • Module integration concepts • Stave • Super module T. Kawamoto

  33. Conclusions • The LHC will continue running well beyond 2020 with upgrades to much higher • luminosity than initially designed. • ATLAS has plans of changes under development to profit as much from the LHC • upgrade. • In 2013/14 shutdown, there will be a new detector element: IBL • In phase-1, new muon small wheel, possibly new warm mini FCAL, new trigger • and other upgrades. • In phase-2, completely new inner tracker, some upgrade of muon chamber, • possibly new forward calorimeter, major upgrade on trigger and DAQ. • Studies and work are under way. T. Kawamoto

  34. Back up T. Kawamoto

  35. ATLAS status T. Kawamoto

  36. ATLAS status Etmiss, Btag T. Kawamoto

  37. ATLAS status Some performance figures T. Kawamoto

  38. ATLAS upgrade : phase - 2 Trigger for phase-2 • Rates are 5x higher than at nominal luminosity. • Event size will also be bigger : many interactions/crossing. • Cannot increase the recording rate of these big events significantly. • But need to maintain (reasonably) low threshold for leptons, jets, ETmiss, etc • for physics acceptance. • Much higher rejection needed at all levels of trigger (L1, L2, Event filter) • Improvements considered are: • More processing at L1 : e.g. topology info • Sharpening threshold for leptons and calorimeter energy • Longer L1 latency will be needed: 3ms → 6 or 9 or even longer, or L0/L1 scheme • Possible ID-track trigger T. Kawamoto

  39. ATLAS upgrade : phase - 2 Calorimeters • Barrel calorimeters will work OK : no changes needed. • Endcap cold electronics (preamplifiers for Hadron endcap) in cryostat • may or may not survive (designed for 1000 fb-1). • If it survives, the phase-1 mini FCAL would be sufficient • to protect FCAL from ion build up, HV drop, heat problem • If proven necessary to change the cold electronics, • need to open the cryostat • → major work, 18 months should be OK • Replace cold electronics with rad-hard elec. • Replace FCAL with smaller gap design. T. Kawamoto

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